Windows Help Internal Variables

The information in this article applies to:

• Microsoft Windows Software Development Kit (SDK) for Windows version 3.1

SUMMARY

The following information on the Windows Help internal variables is from the Help Authoring Guide on the Microsoft Developer's Network (MSDN) CD:

   Windows Help defines a series of internal variables that can be used
   with macros. After you register a DLL function as a Help macro, you can
   specify the Windows Help internal variables as parameters to that
   function when the function appears in hot spots or macro footnotes.
   These variables are always available, and their values change depending
   on the current state of the Help file. Many DLL routines, as well as
   some standard Help macros, require the information residing in these
   variables.

   You can use any of the following Windows Help internal variables in DLL
   functions:

   Variable      Format Spec   Description
   ---------------------------------------

   hwndApp       U             Number specifying the handle (a numeric
                               identifier used by Windows) to the main
                               Help window. This variable is guaranteed
                               to be valid only while the DLL function is
                               executing.

   hwndContext   U             Number specifying the handle of the Help
                               window (either the main Help window or a
                               secondary window) that is active at the
                               time the DLL is called.

   qchPath       S             String specifying a fully qualified path
                               of the currently open Help file.

   qError        U             Long pointer to a structure containing
                               information about the most recent Windows
                               Help error.

   lTopicNo      U             Number specifying the current topic
                               number. This number is relative to the
                               order of topics in the RTF files used to
                               build the Help file. The current topic is
                               the topic displayed in the Help window
                               that is active when the DLL is called.

   hfs           U             Number specifying the handle (a numeric
                               identifier used by Windows) to the file
                               system for the currently open Help file.

   coForeground  U             Number specifying the RGB value of the
                               foreground color of the window that is
                               active when the DLL is called.

   coBackground  U             Number specifying the RGB value of the
                               background color of the window that is
                               active when the DLL is called.